The ADS131A0x offers an integrated watchdog timer to protect the device from entering an unresponsive state. Enable the watchdog timer by setting the WDT_EN bit in the D_SYS_CFG register. The timer resets with each data frame when the CS signal transitions from high to low. If a timer reset does not take place, the watchdog timer expires after 500 ms and checks the status of the DONE pin.
If DONE is high when the watchdog timer expires, the device assumes that an unresponsive state has occurred and issues a watchdog timer reset. Following the reset, the device enters the power-up state (see the Power-Up section) and sets the F_WDT bit in the STAT_1 register, indicating that a watchdog timer reset has taken place. After this watchdog reset, the device requires re-initialization, as if powering up the device for the first time.
If DONE is low when the watchdog timer expires, the device itself has completed the communication frame and assumes that there is an issue in the system itself outside the device. In this case, the device sets the F_WDT bit in the STAT_1 register without resetting the device to preserve the configuration.
The watchdog timer feature is useful for devices connected in a daisy-chain communication. With a synchronous master and synchronous slaves in chain, the watchdog timer can determine if a device has become unresponsive so that the device can be reset and then re-initialized. By default, the watchdog timer is not enabled.